A tax write-off is any expense the IRS allows you to subtract from your taxable income, reducing the amount of tax you owe. Some write-offs are available to nearly everyone (the standard deduction), while others require you to be self-employed, run a business, or itemize your personal deductions. The key question isn’t just “can I write this off?” but whether the expense meets specific IRS criteria and whether you have the records to prove it.
The Two Main Types of Write-Offs
Tax write-offs fall into two broad buckets: personal deductions you claim on your individual return, and business deductions you claim against self-employment or business income. They work differently and have different rules.
On the personal side, you choose between the standard deduction and itemized deductions. For tax year 2026, the standard deduction is $16,100 for single filers, $32,200 for married couples filing jointly, and $24,150 for heads of household. If your total itemizable expenses don’t exceed those amounts, the standard deduction gives you a bigger tax break and you don’t need to track individual expenses at all. Most taxpayers take the standard deduction for exactly this reason.
Business deductions are separate. If you’re self-employed or own a business, you deduct qualifying expenses on Schedule C (or through your business entity’s return) before your income ever hits your personal return. You get these deductions regardless of whether you also take the standard deduction on the personal side.
What Makes a Business Expense Deductible
The IRS uses a two-word test: the expense must be “ordinary and necessary.” An ordinary expense is one that’s common and accepted in your industry. A necessary expense is one that’s helpful and appropriate for your trade or business. The IRS specifically notes that an expense doesn’t have to be indispensable to qualify as necessary. It just has to make sense for the work you do.
A graphic designer buying a subscription to design software passes both tests easily. A real estate agent paying for professional photography of a listing is ordinary in that industry and clearly helpful. Where it gets murkier is expenses that straddle the line between personal and business use, like a phone you use for both work calls and personal scrolling, or a car you drive to client meetings and also to the grocery store. In those cases, you can only deduct the business-use portion.
Common Business Write-Offs
If you’re self-employed or run a small business, these categories make up the bulk of what most people deduct:
- Vehicle mileage: For 2026, the standard mileage rate is 72.5 cents per mile driven for business. You can use this flat rate instead of tracking actual gas, insurance, and maintenance costs. Either way, you need a log of your business trips showing the date, destination, business purpose, and miles driven.
- Home office: If you use a dedicated space in your home regularly and exclusively for business, you can deduct a portion of your rent or mortgage interest, utilities, and insurance based on the square footage of that space relative to your whole home. The IRS also offers a simplified method that lets you deduct $5 per square foot, up to 300 square feet. The key word is “exclusively.” A kitchen table where you also eat dinner doesn’t qualify.
- Supplies and equipment: Office supplies, computers, software subscriptions, tools, and machinery used in your business are deductible. For larger purchases like equipment or furniture, you can often deduct the full cost in the year you buy it (called a Section 179 deduction) rather than spreading it out over several years through depreciation.
- Professional services: Fees paid to accountants, lawyers, consultants, or contractors who do work for your business.
- Marketing and advertising: Website hosting, business cards, online ads, signage, and promotional materials.
- Insurance: Premiums for business liability insurance, professional malpractice coverage, and similar policies. Self-employed individuals can also deduct health insurance premiums for themselves and their families, though this is taken as an adjustment to income rather than a Schedule C expense.
- Education and training: Courses, workshops, and certifications that maintain or improve skills required in your current business. A freelance web developer taking an advanced coding course qualifies. That same developer getting a degree in an entirely unrelated field likely does not.
- Travel and meals: Airfare, hotels, and transportation for business trips are fully deductible. Business meals (with a client, vendor, or colleague where business is discussed) are generally 50% deductible.
Personal Deductions Worth Itemizing
If your total personal deductions exceed the standard deduction, itemizing saves you more. The most common itemized deductions include:
- State and local taxes (SALT): You can deduct state income taxes (or state sales taxes, but not both) plus local property taxes, up to a combined cap of $10,000 per return.
- Mortgage interest: Interest on up to $750,000 of mortgage debt on your primary home or a second home.
- Charitable contributions: Donations to qualified nonprofits, whether cash or property. Cash donations are generally deductible up to 60% of your adjusted gross income. Keep receipts, and for any single donation of $250 or more, you need a written acknowledgment from the organization.
- Medical expenses: Out-of-pocket medical and dental costs that exceed 7.5% of your adjusted gross income. If you earn $60,000 and have $6,000 in medical bills, only the amount above $4,500 (7.5% of $60,000) is deductible, giving you a $1,500 write-off.
For most people earning moderate incomes, the standard deduction is higher than the sum of these expenses. Itemizing tends to benefit homeowners with large mortgages, people in high-tax states, or those with significant medical bills or charitable giving.
What Doesn’t Count as a Write-Off
The line between deductible and non-deductible often comes down to personal versus business use. A few expenses trip people up regularly:
Clothing you could wear outside of work isn’t deductible, even if you only wear it to the office. A shirt with your company logo that everyone on staff is required to wear qualifies. A blazer you bought because it looks professional does not. The test is whether the clothing is unsuitable for everyday wear or required as a uniform.
Your cell phone bill isn’t automatically a write-off just because you take work calls on it. If it’s your only phone and you use it for personal calls, texts, and social media, you can only deduct the percentage that reflects actual business use. You’ll need call logs or usage records to back that up.
Commuting costs, meaning the drive from your home to your regular workplace, are never deductible. Driving from your office to a client site, or from one job location to another during the workday, is deductible. The IRS draws a firm line between commuting and business travel.
Unpaid invoices are another common misconception for service-based businesses. If a client never pays you, you can’t deduct the amount as a loss because you never reported it as income in the first place (assuming you use cash-basis accounting, which most small businesses do). You simply don’t include that payment in your revenue.
Records You Need to Keep
A write-off only holds up if you can prove it. The IRS expects you to keep supporting documents that show the payee, amount paid, date, proof of payment, and a description of what the expense was for. Acceptable records include receipts, canceled checks, bank and credit card statements, and invoices. A combination of documents may be needed to fully substantiate a single expense.
Electronic records are perfectly fine. Accounting software, scanned receipts, or photos of paper receipts stored in the cloud all meet IRS requirements, as long as they capture the same information a paper record would. The IRS generally recommends keeping records for at least three years from the date you file your return, though certain situations (like claiming a loss from worthless securities) extend that to seven years.
For vehicle expenses, keep a mileage log with the date of each trip, where you went, the business purpose, and the odometer readings. For assets like equipment or furniture, hold onto purchase invoices, records of any improvements, and documentation of how the asset was used in your business. If you ever sell or dispose of the asset, you’ll need records of the sale price and any related expenses.
The simplest approach is to use a dedicated business bank account and credit card for all business spending. Every transaction creates an automatic paper trail, and at tax time you’re not scrolling through personal purchases trying to flag the deductible ones.